The present invention relates to a camera having a liquid crystal display (LCD) in a finder.
There are known various prior-art techniques wherein an LCD is used for display in a finder of a camera.
The LCD displays, for example, an AF (auto-focus) target mark, various photographing modes, and switching of the angle of view for, e.g. a panorama picture or a normal picture. The types of conventionally used LCDs are, for example, so-called Guest Host type LCDs and TN (Twisted Nematic) type LCDs.
It has recently been proposed, as described in Japanese Patent Application KOKAI Publication No. 5-165017, to use a high-molecular dispersion type liquid crystal for an LCD in the finder of the camera. The high-molecular dispersion type liquid crystal described in this prior-art publication is a so-called positive type liquid crystal which takes a non-transmissive state when a voltage is applied, and takes a transmissive state when a voltage is not.
On the other hand, there is known a so-called negative-type high-molecular dispersion type liquid crystal which takes a transmissive state when a voltage is applied, and takes a non-transmissive state when a voltage is not.
The LCD using the high-molecular dispersion type liquid crystal has a high degree of dispersion and, where it is used in the finder of the camera, the intensity of light arriving at the eye is very weak. Accordingly, compared to the Guest Host type or TN type, a finder with high contrast can be fabricated.
Even in conventional Guest Host type LCDs, there are negative-type ones. In these years, various kinds of liquid crystals have become applicable to the finder of the camera.
In the meantime, a vigorous developmental effort is in progress to achieve full automatic operations of cameras, and in some types of cameras a photographing operation is automatically prohibited in situations which do not permit photographing.
Such cameras, however, have problems. In particular, the user may inadvertently attempt a photographing operation in such situations requiring a prohibition of photographing, which may easily occur to any users, that a film has been rewound but not yet been removed or a new film has been set but an auto-load operation for preparation of photographing has failed.
The object of the present invention is to provide a camera which enables a user to exactly determine whether a photographing-prohibition state has occurred or not, only by viewing a liquid crystal display (LCD).
In order to achieve this object, according to a first aspect of the invention, there is provided a camera comprising: a liquid crystal display with a variable transmissivity, disposed within a finder; camera operation means for executing predetermined camera operations; determination means for determining whether the camera operation means is normal or whether the predetermined camera operations have normally been executed; and liquid crystal control means for varying the transmissivity of the liquid crystal display on the basis of a determination result of the determination means.
According to a second aspect of the invention, there is provided a camera comprising: a liquid crystal display with a variable transmissivity, disposed within a finder; film feed means for feeding a film; and liquid crystal control means for temporarily lowering a transmissivity of the liquid crystal display after a film rewinding operation by the film feed means is completed.
According to a third aspect of the invention, there is provided a camera comprising: a liquid crystal display disposed within a finder; film feed means for feeding a film; and liquid crystal control means for controlling the liquid crystal display such that a transmissivity of the finder varies, when a film rewinding operation by the film feed means is completed.
According to a fourth aspect of the invention, there is provided a camera comprising: a liquid crystal display device disposed within a finder; a liquid crystal drive circuit for driving the liquid crystal display device; a film feed mechanism for feeding a film loaded in the camera; and a CPU for controlling the film feed mechanism to execute a rewinding operation for rewinding the film and, after completion of the rewinding operation, varies a transmissivity of the liquid crystal display device through the liquid crystal drive circuit.
According to a fifth aspect of the invention, there is provided a camera comprising: a film loading chamber in which a film is to be loaded; a film loading chamber cover for opening and closing the film loading chamber; a liquid crystal display disposed within a finder; film feed means for executing an auto-loading windup operation for the film when the film is put in the film loading chamber and the film loading chamber cover is closed; and liquid crystal control means for lowering a transmissivity of the finder when the auto-loading windup operation by the film feed means has failed.
According to a sixth aspect of the invention, there is provided a camera comprising: a liquid crystal display disposed within a finder; film feed means for executing an auto-load windup feeding operation for a film; determination means for determining whether the auto-load windup feeding operation by the film feed means has normally been executed; and liquid crystal control means for controlling a transmissivity of the liquid crystal display on the basis of a determination result of the determination means.
According to a seventh aspect of the invention, there is provided a camera comprising: a liquid crystal display disposed within a finder; release signal output means for outputting a release signal; exposure means for performing an exposure operation in accordance with the release signal output from the release signal output means; determination means for determining whether an exposure operation of the exposure means is normal; and liquid crystal control means for controlling a transmissivity of the liquid crystal display on the basis of a determination result of the determination means.
According to an eighth aspect of the invention, there is provided a camera comprising: a liquid crystal display disposed within a finder; release signal output means for outputting a release signal; exposure means for performing an exposure operation in accordance with the release signal output from the release signal output means; determination means for determining a fault of the exposure means; and liquid crystal control means for temporarily lowering a transmissivity of the liquid crystal display in response to the operation of the exposure means, where no fault of the exposure means is determined by the determination means.
According to a ninth aspect of the invention, there is provided a camera comprising: a liquid crystal display device disposed within a finder; a liquid crystal drive circuit for driving the liquid crystal display device; a release switch for outputting a release signal; a shutter for controlling an exposure amount for a film; a shutter drive mechanism for driving the shutter; a photo-interrupter for outputting a signal when the shutter is set in an open state; and a CPU for outputting a control signal to the liquid crystal drive circuit such that the liquid crystal display device is set in a light-non-transmissive state, where the signal from the photo-interrupter is detected within a predetermined time period after the shutter drive mechanism is operated in response to the release signal from the release switch.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.